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72 lines
2 KiB
Python
72 lines
2 KiB
Python
# -*- coding: utf-8 -*-
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from PIL import Image
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def encode_image(img, msg):
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"""
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use the red portion of an image (r, g, b) tuple to
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hide the msg string characters as ASCII values
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the red value of the first pixel is used for length of string
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"""
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length = len(msg)
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# limit length of message to 255
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if length > 255:
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return False
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# use a copy of image to hide the text in
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encoded = img.copy()
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width, height = img.size
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index = 0
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for row in range(height):
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for col in range(width):
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(r, g, b) = img.getpixel((col, row))
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# first value is length of msg
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if row == 0 and col == 0 and index < length:
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asc = length
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elif index <= length:
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c = msg[index -1]
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asc = ord(c)
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else:
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asc = r
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encoded.putpixel((col, row), (asc, g , b))
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index += 1
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return encoded
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def decode_image(img):
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"""
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check the red portion of an image (r, g, b) tuple for
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hidden message characters (ASCII values)
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the red value of the first pixel is used for length of string
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"""
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width, height = img.size
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msg = ""
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index = 0
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for row in range(height):
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for col in range(width):
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r, g, b = img.getpixel((col, row))
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# first pixel r value is length of message
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if row == 0 and col == 0:
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length = r
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elif index <= length:
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msg += chr(r)
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index += 1
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return msg
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original_image_file = "./pictures/Lenna.png"
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encoded_image_file = "./pictures/Lenna_enc.png"
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img = Image.open(original_image_file)
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# at this point don't exceed 255 characters
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secret_msg = "Parce que je le vaut bien!"
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img_encoded = encode_image(img, secret_msg)
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if img_encoded:
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# save it ...
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img_encoded.save(encoded_image_file)
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# test it ...
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img2 = Image.open(encoded_image_file)
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print(decode_image(img2))
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else:
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print("text too long! (don't exeed 255 characters)")
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